Experimental study on coupling relationship between crack evolution and seismic source signals of filling body

Abstract：Macroscopic crack propagation and microseismic source signal accumulation are often regarded as two kinds of key informations to analyze the fracture process of filling body, but there is less direct and definite experimental verifications on temporal and spatial coupling relationship, which is not conducive to the comprehensive analysis of the damage characteristics of filling body.Based on acoustic emission positioning system and Geiger localization algorithm, the three-dimensional dynamic evolution model of tailings cemented filling body under uniaxial loading was studied.Compared with the temporal and spatial distribution of the seismic source signals, the results showed that there was a positive correlation between acoustic emission events and stress-strain as mechanical responses.The macroscopic crack evolution of filling body and the gathering of mesoscopic seismic source signals had good temporal-spatial coupling.Acoustic emission location could accurately reflect the dynamic evolution process of internal source signal derivation, aggregation and extension.The distribution of internal cracks in three-dimensional space could be effectively tracked.Acoustic emission activity was not obvious during initial loading period.In the stable growth period of the crack, the source signals gradually clustered into central area (C area) of the sample, taking C-area as the core, the inner connected spherical three-dimensional spatial region with radioactivity spreading appeared some uneven scattered points, and the acoustic emission events rised steadily.After the peak strength, the depth of the C-area extended into a column zonation, and the seismic source was located in the sphere-area (S area) .The acoustical emission event of the specimen increases steeply and the activity of the acoustic emission approached to the extreme value due to the failure of the through-through fracture of the specimen.Based on the results of acoustic emission localization, the nucleate main seismic area and its forming extension direction, curved surface shape, it could be reasonably predicted for the rupture source and failure form in the indoor filling loading tests.These provided a new way to study the failure mechanism of backfill body.

Keyword：filling body;acoustic emission location;Geiger algorithm;crack evolution;main seismic source;